1. Field of the Invention
The present invention relates to a manipulator having a distal end working unit which includes an end effector.
2. Description of the Related Art
According to a laparoscopic surgical operation process, some small holes are opened in the abdominal region, for example, of a patient and an endoscope and manipulators or forceps are inserted into the holes. The surgeon performs a surgical operation on the patient with the manipulators or forceps while watching an image captured by the endoscope and displayed on a display monitor. Since the laparoscopic surgical operation process does not require a laparotomy, it is less burdensome on the patient and greatly reduces the number of days required for the patient to spend before recovering from the operation or being released from the hospital, it is expected to increase a range of surgical operations to which it is applicable.
Manipulators for laparoscopic surgical operations are required to allow the operator, i.e., the surgeon, to perform various appropriate techniques quickly depending on the position and size of the affected part, for removing, suturing, and ligating the affected part. The applicants have proposed manipulators which can be manipulated simply with a high degree of freedom (see, for example, JP 2002-102248 A and JP 2004-301275 A).
When the surgeon uses forceps of the general nature in a flexible scope surgery or a laparoscopic surgery, external forces applied to the distal end working unit of the forceps and gripping forces applied by the distal end working unit are transmitted, not directly, but as reactive forces, to the hand of the surgeon. Therefore, the surgeon can feel those forces to a certain extent and can operate the forceps based on the reactive forces. The forceps that have been available heretofore, however, have few degrees of freedom, e.g., one degree of freedom, are difficult to handle because they are movable only in limited directions to grip and cut tissues and also to insert suture needles, and require surgeons to be skilled in using them.
To achieve higher degrees of freedom, one option is to use a master-slave remote control surgical robot, for example. The master-slave remote control surgical robot is advantageous in that it has high degrees of freedom, can approach the affected part of a patient from various desired directions, and can be operated effectively and efficiently. However, external forces applied to the distal end working unit and gripping forces applied by the distal end working unit are not transmitted to the master side of the master-slave remote control surgical robot.
If a force feeling is to be available on the master side of the master-slave remote control surgical robot, then the surgical robot will need to be an expensive and complex system as it needs a highly sophisticated bilateral control architecture based on a highly sensitive force sensing system and a computer system having high-speed sampling times. In addition, the bilateral control architecture has not yet reached a practically sufficient performance level at present.
The applicants have already proposed multiple-degree-of-freedom forceps including a distal end working unit having joints that can be actuated by motors based on commands from an operating unit. Since the operating unit, i.e., an operating handle, and the working unit, i.e., distal end joints, are integrally coupled to each other, external forces applied to the distal end working unit and gripping forces applied by the distal end working unit are transmitted, not directly, but via the multiple-degree-of-freedom forceps, to the operating unit. Therefore, the operator of the multiple-degree-of-freedom forceps can feel those forces to a certain extent. Nevertheless, there are demands for multiple-degree-of-freedom forceps which allow the operator to feel stronger forces, in particular, multiple-degree-of-freedom forceps which allow the operator to feel stronger gripping forces.